Signal emitting styluses, e.g. active styluses are known in the art for use with a digitizer system. Position detection of the stylus provides input to a computing device associated with the digitizer system and is interpreted as user commands. Often, the digitizer system is integrated with a display screen, e.g. to form a touch screen. Position of the stylus over the screen is correlated with virtual information portrayed on the screen.
Digitizer systems that track signals emitted by the stylus also typically track input provided with a finger or conductive object. A mutual capacitive sensor is one type of digitizer sensor for such digitizer systems. Mutual capacitive sensors typically include a matrix formed with parallel conductive material arranged in rows and columns with a capacitive connection created around overlap and/or junction areas formed between rows and columns. Bringing a finger or conductive object close to the surface of the digitizer sensor changes the local electrostatic field and reduces the mutual capacitance between junction areas in the vicinity. The capacitance change at junctions is determined by applying a signal along one axis of the matrix while sampling output on the other axis to detect a coupled signal. Mutual capacitive detection allows multi-touch operation where multiple fingers, palms or conductive objects can be tracked at the same time. Stylus input may be tracked by sampling output along both axes of the sensor to identify locations on the matrix at which the stylus signal is picked-up.